hbase-client/src/main/java/org/apache/hadoop/hbase/client/RetriesExhaustedException.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.hadoop.hbase.client;

import java.io.IOException;
import java.time.Instant;
import java.time.format.DateTimeFormatter;
import java.util.List;
import java.util.StringJoiner;

import org.apache.commons.lang3.StringUtils;
import org.apache.yetus.audience.InterfaceAudience;

/**
 * Exception thrown by HTable methods when an attempt to do something (like
 * commit changes) fails after a bunch of retries.
 */
@InterfaceAudience.Public
public class RetriesExhaustedException extends IOException {
  private static final long serialVersionUID = 1876775844L;

  public RetriesExhaustedException(final String msg) {
    super(msg);
  }

  public RetriesExhaustedException(final String msg, final IOException e) {
    super(msg, e);
  }

  /**
   * Data structure that allows adding more info around Throwable incident.
   */
  @InterfaceAudience.Private
  public static class ThrowableWithExtraContext {
    private final Throwable throwable;
    private final long whenAsEpochMilli;
    private final String extras;

    public ThrowableWithExtraContext(final Throwable throwable, final long whenAsEpochMilli,
        final String extras) {
      this.throwable = throwable;
      this.whenAsEpochMilli = whenAsEpochMilli;
      this.extras = extras;
    }

    @Override
    public String toString() {
      final StringJoiner joiner = new StringJoiner(", ");
      if (whenAsEpochMilli != 0) {
        joiner.add(DateTimeFormatter.ISO_INSTANT.format(Instant.ofEpochMilli(whenAsEpochMilli)));
      }
      if (StringUtils.isNotEmpty(extras)) {
        joiner.add(extras);
      }
      if (throwable != null) {
        joiner.add(throwable.toString());
      }
      return joiner.toString();
    }
  }

  /**
   * Create a new RetriesExhaustedException from the list of prior failures.
   * @param callableVitals Details from the Callable we were using
   * when we got this exception.
   * @param numTries The number of tries we made
   * @param exceptions List of exceptions that failed before giving up
   */
  public RetriesExhaustedException(final String callableVitals, int numTries,
      List<Throwable> exceptions) {
    super(getMessage(callableVitals, numTries, exceptions));
  }

  /**
   * Create a new RetriesExhaustedException from the list of prior failures.
   * @param numRetries How many times we have retried, one less than total attempts
   * @param exceptions List of exceptions that failed before giving up
   */
  @InterfaceAudience.Private
  public RetriesExhaustedException(final int numRetries,
                                   final List<ThrowableWithExtraContext> exceptions) {
    super(getMessage(numRetries, exceptions),
      exceptions.isEmpty()? null: exceptions.get(exceptions.size() - 1).throwable);
  }

  private static String getMessage(String callableVitals, int numTries,
      List<Throwable> exceptions) {
    StringBuilder buffer = new StringBuilder("Failed contacting ");
    buffer.append(callableVitals);
    buffer.append(" after ");
    buffer.append(numTries);
    buffer.append(" attempts.\nExceptions:\n");
    for (Throwable t : exceptions) {
      buffer.append(t.toString());
      buffer.append("\n");
    }
    return buffer.toString();
  }

  private static String getMessage(final int numRetries,
      final List<ThrowableWithExtraContext> exceptions) {
    StringBuilder buffer = new StringBuilder("Failed after attempts=");
    buffer.append(numRetries + 1);
    buffer.append(", exceptions:\n");
    for (ThrowableWithExtraContext t : exceptions) {
      buffer.append(t.toString());
      buffer.append("\n");
    }
    return buffer.toString();
  }
}